Ice nucleating particle concentrations of the past: Insights from a 600 year old Greenland ice core

doi:10.5194/acp-2020-556

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-556
	Ice nucleating particle concentrations of the past: Insights from a 600 year old Greenland ice core
	Jann Schrod, Dominik Kleinhenz, Maria Hörhold, Tobias Erhardt, Sarah Richter, Frank Wilhelms, Hubertus Fischer, Martin Ebert, Birthe Twarloh, Damiano Della Lunga, Camilla Marie Jensen, Joachim Curtius, and Heinz G. Bingemer
	2020-06-17
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	Ice nucleating particles (INPs) affect the microphysics in cloud and precipitation processes. Hence, they modulate the radiative properties of clouds. However, atmospheric INP concentrations of the past are basically unknown. Here, we present INP measurements from an ice core in Greenland, which dates back to the year 1370. In total 135 samples were analyzed with the FRIDGE droplet freezing assay in the temperature range from −14 °C to −35 °C. The sampling frequency was set to 1 in 10 years from 1370 to 1960. From 1960 to 1990 the frequency was increased to 1 sample per year. Additionally, a number of special events were probed, including volcanic episodes. The typical time coverage of a sample was on the order of a few months. Historical atmospheric INP concentrations were estimated with a conversion factor, which depends on the snow accumulation rate of the ice core, particle dry deposition velocity and the wet scavenging ratio. Typical atmospheric INP concentrations were on the order of 0.1 L⁻¹ at −25 °C. The INP variability was found to be about 1–2 orders of magnitude. Yet, the short-term variability from samples over a seasonal cycle was considerably lower. INP concentrations were significantly correlated to chemical tracers derived from continuous flow analysis (CFA) and ion chromatography (IC) over a broad range of nucleation temperatures. The highest correlation coefficients were found for the particle concentration (d_p > 1.2 μm). The correlation is higher for the seasonal samples, where INP concentrations follow a clear annual pattern, highlighting the importance of the annual dust input in Greenland from East Asian deserts during spring. Scanning electron microscopy (SEM) of single particles retrieved from selected samples found particles of soil origin to be the dominant fraction, verifying the significance of mineral dust particles as INPs. Overall, the concentrations compare reasonably well to present day INP concentrations, albeit they are on the lower side. However, we found that the INP concentration at medium supercooled temperatures differed before and after 1960. Average INP concentrations at −23 °C, −24 °C, −25 °C, −26 °C and −28 °C were significantly higher (and more variable) in the modern day period, which could indicate a potential anthropogenic impact or some post-coring contamination of the topmost, very porous firn.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/276542
专题	地球科学
推荐引用方式 GB/T 7714	Jann Schrod, Dominik Kleinhenz, Maria Hörhold, Tobias Erhardt, Sarah Richter, Frank Wilhelms, Hubertus Fischer, Martin Ebert, Birthe Twarloh, Damiano Della Lunga, Camilla Marie Jensen, Joachim Curtius, and Heinz G. Bingemer. Ice nucleating particle concentrations of the past: Insights from a 600 year old Greenland ice core[J]. Atmospheric Chemistry and Physics,2020.
APA	Jann Schrod, Dominik Kleinhenz, Maria Hörhold, Tobias Erhardt, Sarah Richter, Frank Wilhelms, Hubertus Fischer, Martin Ebert, Birthe Twarloh, Damiano Della Lunga, Camilla Marie Jensen, Joachim Curtius, and Heinz G. Bingemer.(2020).Ice nucleating particle concentrations of the past: Insights from a 600 year old Greenland ice core.Atmospheric Chemistry and Physics.
MLA	Jann Schrod, Dominik Kleinhenz, Maria Hörhold, Tobias Erhardt, Sarah Richter, Frank Wilhelms, Hubertus Fischer, Martin Ebert, Birthe Twarloh, Damiano Della Lunga, Camilla Marie Jensen, Joachim Curtius, and Heinz G. Bingemer."Ice nucleating particle concentrations of the past: Insights from a 600 year old Greenland ice core".Atmospheric Chemistry and Physics (2020).